1. Field of the Invention
The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display and a fabricating method thereof enabling to improve an opening ratio of the liquid crystal display by modifying a structure of a thin film transistor.
2. Discussion of the Related Art
Generally, a liquid crystal display includes a lower substrate having thin film transistors and pixel electrodes arranged thereon, an upper substrate having color filters for realizing colors and common electrodes, and liquid crystals inserted between the upper and lower substrates. In this case, light transmittance of the liquid crystals varies in accordance whether a voltage is applied thereto or not so as to display an image.
Namely, on the lower substrate are formed a plurality of gate lines arranged in one direction so as to leave a predetermined interval from each other, a plurality of data lines arranged in a direction perpendicular to the gate lines with a predetermined interval from each other so as to define matrix type pixel areas, respectively. A plurality of pixel electrodes are formed in the pixel areas, respectively. And, a plurality of thin film transistors are formed at intersections between the gate and data lines so as to apply data signals of the data lines to the corresponding pixel electrodes in accordance with signals of the gate lines, respectively.
On the upper substrate are formed black matrix layers cutting off light from portions corresponding to the gate lines, data lines, and thin film transistors on the lower substrate, R, G, and B color filter layers at portions corresponding to the pixel areas, respectively, and common electrodes on the color filter layers, respectively.
Since the black matrix layers are formed to cut off light from the portions where the thin film transistors are formed in the general liquid crystal display, an opening ratio is reduced corresponding to the portions where the thin film transistors are formed.
A constitution of a thin film transistor in a liquid crystal display according to a related art is explained as follows.
FIG. 1 illustrates a layout of a thin film transistor in a general liquid crystal display.
Namely, a gate line 1 having a gate electrode 1a is arranged in one direction with a predetermined interval from other gate lines on a substrate(not shown in the drawing), and a gate insulating layer(not shown in the drawing) is formed on an entire surface. A semiconductor layer 3 as an active layer of a thin film transistor is formed like an island on the gate insulating layer over the gate electrode 1a, and a data line 2 having a source electrode 2a is arranged on the gate insulating layer with a predetermined interval in a direction perpendicular to the gate line 1 so as to define a pixel area. In this case, the gate and source electrodes 1a and 2a are formed at the pixel area at an intersection between the gate and data lines 1 and 2, and the source electrodes 2a extends from the data line 2 so as to be overlapped with the semiconductor layer 3.
And, a drain electrode 2b is formed on the semiconductor layer 3 at a side opposite to the source electrode 2a so as to complete a thin film transistor(TFT). Besides, a pixel electrode 4 is formed in the pixel area so as to be connected to the drain electrode 2b. 
Unfortunately, the thin film transistor in the general liquid crystal display has the following disadvantages or problems.
First, the thin film transistor is formed at the specific area in the pixel area, thereby reducing an opening ratio of the liquid crystal display.
Second, since the source electrode extends from the data line so as to be overlapped with the gate electrode, the parasitic capacitance formed between the gate and source electrodes, is not uniform for various reasons including misalignment during fabrication which causes flickering of the liquid crystal display.